Its 40,000 residents on the banks of Lake Erie had in every election since 1944 voted for the candidate who went on to win Ohio, the state that had in every election since 1964 voted for the man who went on to win the White House. Like George W Bush and Barack Obama before him, Mr Romney would probably need to swing it his way to win Ohio's precious 18 electoral college votes.

Yet his troops were nowhere to be found. Anyone stumbling across the Romney office in Port Clinton -- a brightly-lit empty shop -- were greeted by Justine and John, an elderly and hard-of-hearing married couple, who were neatly stacking piles of stickers and leaflets.

Meanwhile, in a shabbier office just five minutes away, Olivia, a graduate of a prestigious university who had been parachuted in from New York, was directing energetic young volunteers using a sophisticated direct-dialling software system to methodically make phone calls urging for the re-election of Mr Obama.

Politely but insistently, they asked how residents planned to vote, when they planned to vote, and whether someone could visit them to drive them to a polling station right away. Teams of cheerful canvassers were meanwhile fanning out across the county, using a tight script to persuade the undecided at the doorstep.

On Tuesday Mr Obama won Ottawa by four percentage points, triumphed in Ohio and secured another four years in the White House. Except for North Carolina, a traditionally conservative state, he looked likely to have won all the battleground states, including Florida, by replicating this bombardment.

The sharply contrasting picture of campaigning in such politically crucial areas of the country is emblematic of the vastly superior "ground game" played by Mr Obama's campaign around the US to crush Mitt Romney's presidential efforts, in a year when the incumbent president should by rights have badly struggled.

Mr Obama prevailed by using this supercharged and digitally-driven get-out-the-vote machine to hold together the coalition of ethnic minorities, young women, students and the liberal urban classes.

Maximise

The raw numbers were mind-boggling: more than 125 million personal phone calls to voters, 1.7 million new voters registered, 700,000 canvassing shifts and 5,100 hyper-local 'hubs' designed to maximise every last ounce of traditional Democrat advantage in early voting.

This army of footsoldiers was allied to the celebrity pulling power of artists like the rocker Bruce Springsteen, hip-hop maestro Jay-Z and, for the kids, the pop talents of Katy Perry, who ensured massive attendance at Mr Obama's closing events.

Mr Obama's backers in Hollywood, such as George Clooney and Sarah Jessica Parker, were used to snare the big donors at $50,000-a-plate dinner parties for the liberal elite. However, less appreciated was the importance of campaign lotteries for a chance to dine with "Sarah Jessica" or "George". In entering, young supporters handed over precious personal information that enabled Obama For America to add to its already-unrivalled database, which it then mined to startling effect for donations, attendance at events and eventually voters.

The precise algorithms were closely guarded secrets -- "our nuclear codes", as one senior campaign strategist called them. However, by combining biographical information with consumer habit data, the campaign was able to micro-target both donors and voters with unmatched efficiency.